1. Field of the Invention
The present invention relates to toy music boxes and, particularly, to toy music boxes powered by the motion of air.
2. Technical Background
Toy music boxes that are driven by an air actuated propeller are known. Generally these devices are held in a stationary position while a continuous motion of ambient air turns a propeller and rotates a drum cylinder inside the music box at a speed proportional to the speed of the air to produce music. If air speed is variable the tempo of the music is variable. If there is no motion of ambient air, the propeller can be activated by a user moving the music box through the air manually, but it is extremely difficult, if not impossible to generate a relatively constant rotation of the drum cylinder. The resulting music has an unacceptable variation in tempo which is unsuitable for the intended purpose of the music box. Heretofore there has been no practical means to govern the power transmitted to the drum cylinder in a toy music box to produce a constant tempo melody as the music box is moved manually back and fourth through the air by the user.